/* Copyright  2009
   @Author
   Richard Changde Yin            e-mail yinchangde@hotmail.com

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
/**
 *@filename: cost_vect.h
 */

#ifndef __COST_VECT_H__
#define __COST_VECT_H__

#include <stdint.h>

class COST_VECT
{
public:
  double io_count;     /* number of I/O                 */
  double avg_io_cost;  /* cost of an average I/O oper.  */
  double cpu_cost;     /* cost of operations in CPU     */
  double mem_cost;     /* cost of used memory           */
  double import_cost;  /* cost of remote operations     */

  static const uint32_t IO_COEFF    =1;
  static const uint32_t CPU_COEFF   =1;
  static const uint32_t MEM_COEFF   =1;
  static const uint32_t IMPORT_COEFF=1;

  COST_VECT() {}        // keep gcc happy

  inline double total_cost()
  {
    return IO_COEFF*io_count*avg_io_cost + CPU_COEFF * cpu_cost +
      MEM_COEFF*mem_cost + IMPORT_COEFF*import_cost;
  }

  inline void zero()
  {
    avg_io_cost= 1.0;
    io_count= cpu_cost= mem_cost= import_cost= 0.0;
  }

  inline void multiply(double m)
  {
    io_count *= m;
    cpu_cost *= m;
    import_cost *= m;
    /* Don't multiply mem_cost */
  }

  inline void add(const COST_VECT* cost)
  {
    double io_count_sum= io_count + cost->io_count;
    add_io(cost->io_count, cost->avg_io_cost);
    io_count= io_count_sum;
    cpu_cost += cost->cpu_cost;
  }
  inline void add_io(double add_io_cnt, double add_avg_cost)
  {
    double io_count_sum= io_count + add_io_cnt;
    avg_io_cost= (io_count * avg_io_cost +
                  add_io_cnt * add_avg_cost) / io_count_sum;
    io_count= io_count_sum;
  }
};

void get_sweep_read_cost(Table *table,
                         ha_rows nrows,
                         bool interrupted,
                         COST_VECT *cost);

#endif /* __COST_VECT_H__ */
